Train acrobatics by jumping. OK, that one is obvious, here's a better tip. If you fall and take damage, that increases your acrobatics by much more than just jumping. It doesn't matter if it's only a little bit of damage, in fact it makes no difference how much damage you take, as long as you take some damage. You can train two or three things at once by casting a spell while jumping, which will increase your acrobatics skill even further. Then when you land, use a restoration spell to work on that too.

If you just want to train acrobatics as you go, jump while you're going around town running errands. It's not a good idea to do this out in the wild or in a cave, etc. The reason is jumping will reduce your fatigue, this will make you less effective in combat and while casting spells. If you encounter an enemy you'll be vulnerable if you've been jumping constantly.